Blue whales sighted off Irish coast

September 2008. On Monday 15th September a boat from Kerry Marine Tours (www.kerrymarinetours.com/) of South West Ireland were taking clients on a fishing trip, and were looking for Albacore tuna on a pelagic trip to offshore shelf waters. On board was IWDG Dublin member Ivan O' Kelly who has been taking part in these exploratory fishing cruises, which also have a whale watching component as and when opportunities arise.Fin whales were found associating with the tuna and both species appeared to be feeding on Euphausiid, a species of krill.

1-2 very large whalesOn Monday afternoon 15/09/08 at least one, and probably two, very large whales approached the MV Atlantic Explorer close enough for Ivan to take a few images using a 300mm lens. Ivan forwarded these images and details of the sighting to IWDG, not quite realising the importance of his discovery.

It was clear that among the fin whales he had photographed he had also secured images of a different species, which IWDG can confirm are blue whales. It may even be possible to attempt to Photo Identify at least one of the blue whales. Identification was confirmed by their very pale colouration, unique mottling pattern and the thick muscular column which runs along the back of Blue whales. Later images also showed their diagnostically tiny dorsal fin, which is the only "unimpressive" feature of the planets largest animal.

Blue whale sighted off Ireland. Credit Ivan O'Kelly.

First confirmed sightingThis is the 1st validated sighting of a blue whale in any Irish waters since the IWDG began almost 20 years ago, though there was a possible sighting made in the late 1990's. There are only two stranding records of blue whales on the Irish coast, the last of which was in Bantry Bay, Co. Cork in 1957 and before that on Magilligan Strand, Co. Derry in 1907. Even with today's relatively high level of offshore cetacean survey activity by researchers and marine mammal observers alike, sightings of this species remain extremely rare events, reflecting both their preference for offshore shelf edge waters and their globally low numbers as a result of decades of exploitation by commercial whale fisheries.

Acoustic studies indicate 50 Blue whales pass IrelandThat said, acoustic monitoring studies in the North Atlantic by Chris Clarke of Cornell University, USA has indicated that upwards of 50 blue whales pass through Irish offshore waters late Autumn/early winter on what is presumably a southbound migration. So hopefully this sighting will herald the beginning of a new era, in which blue whales will continue to recover and begin to return to our inshore waters, in the same way as their smaller cousins the fin and humpback whales.

Tracking Blue whales in the AtlanticThe images have been sent to Richard Sears, Quebec, for matching. Richard has among other things been working on the North Atlantic blue whale catalogue for many years. The catalogue currently has 430 individuals, most of which are from the Gulf of St. Lawrence (GSL), but some photos are from Iceland, Greenland, Azores and Mauritania.

Blue whale fluke, off Ireland. Credit Dave Wall.

There are photographic matches between

Greenland and the GSL

Iceland and GSL

Iceland and Mauritania

The Gulf of Maine (Massachusetts) and the GSL.

So fingers crossed these images will reveal some interesting facts about this individual.

Second sightingHaving waited so long for a blue whale sighting, to receive two separate sightings of this flagship species from two different areas over a three day period would seem too good to be true.But just two days after Ivan O Kelly's blue whale encounter, IWDG confirmed a second blue whale encounter along the north slopes of the Porcupine Bank from the RV Celtic Explorer on 17th September.

QuestionsThis week's sightings raise many fascinating questions. Were these always out there, but just nobody seeing them? Or is there an actual increase in blue whales passing through our offshore waters, or do these sightings reflect a change in their distribution?

Read the comments about this article and leave your own comment

There are no matches between the St Lawrence and Iceland. There are matches between the other areas mentioned in the article.

Posted by: Richard Sears | 24 Apr 2009 05:26:47

About matches between areas.

Posted by: Richard Sears | 24 Apr 2009 05:25:35

Blue whale catalogs

My comment is to do with the number of whales in our blue whale catalogs and this article does not get the numbers right, which may just have been due to lack of clarity between me and Pádraig.

Since 1979 we have IDed 430 for the western North Atlantic, which includes blues from the St Lawrence, Scotian Shelf, West Greenland, NFLD, and Gulf of Maine. However, we have an eastern North Atlantic catalog which includes 140 blues from Iceland, 120 from the Azores, plus the two above , 5 from NW Africa, I from Spitsbergen, I from Jan Mayen, and 4 from Atlantic Spain. There are many from the eastern North Atlantic that still need to go through a thorough matching process and so we do not have all results in hand at this time. Just wanted this article to be as accurate as possible. I can be called at 450 465 9176 or contacted by email .